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vfs: reduce failing trylock attempts in mnt_vnode_next_active
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Authored by mjg on Oct 11 2019, 6:45 PM.

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Reviewers
kib
Summary

When doing poudriere -j 104, after 4 minutes of tracing:

kernel`mnt_vnode_next_active                        _mtx_trylock_flags_int                                            1          1683089
kernel`mnt_vnode_next_active                        _mtx_trylock_flags_int                                            0          4781020

That is, majority of attempts to trylock has failed.

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Event Timeline

mjg created this revision.Oct 11 2019, 6:45 PM
mjg retitled this revision from vfs: reduce failing trylock attempts in nt_vnode_next_active to vfs: reduce failing trylock attempts in mnt_vnode_next_active.Oct 11 2019, 6:45 PM
kib added a comment.Oct 11 2019, 8:23 PM

This cannot go in without explanation why mtx_owner is checked, in the comment above. But it should not go in regardless, if such check is useful perhaps it should be added to VI_TRYLOCK, or mtx_trylock, or another version of VI_TRYLOCK created.

mjg updated this revision to Diff 63167.Oct 11 2019, 8:41 PM
  • add VI_TRYLOCK_CONTENDED
kib accepted this revision.Oct 11 2019, 8:56 PM
This revision is now accepted and ready to land.Oct 11 2019, 8:56 PM
mjg abandoned this revision.Sat, Dec 7, 1:24 AM

With filtering support (D22690) this should not be needed